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US5787193A Expired / Lapsed US ⏱️ 0.0 years remaining

System for converting color image signals from RGB to CMY color spaces through look-up tables

Assignee: Xerox Corp
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Filing: 1996-09-27
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Granted: 1998-07-28
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Expires: 2016-09-27
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Abstract

Abstract A system for converting RGB color signals to CMY or CMYK color signals, such as to operate a color printing apparatus, utilizes three separate electronic look-up tables. Each look-up table allows inputs of RGB signals, which are applied to a three-dimensional space. Each point in the space represents an output for one CMY color signal, and each look-up table is dedicated to one CMY color output. Each look-up table emphasizes one particular RGB color, by providing a higher resolution of inputs along the axis for that color.

Inventors

  • 👤 Raja Balasubramanian

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-09 21:21
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/46; H04N1/56; H04N1/60; H04N1/6016; H04N1/6019

Claims Analysis

Total Claims: 11
Claim 1
Independent Claim 337 words
An apparatus for converting color signals representing at least a first color and second color of a first type to color signals representing at lease a first color and second color of a second type, comprising: a first look-up table and a second look-up table, each look-up table being a multi-dimensional look-up table defined in a memory accessible in real time and having as inputs predetermined color signals representing at least the first color and second color of said first type; the first look-up table providing an output for each of a set of combinations of inputs signals representing the first color and second color of said first type, each output being a color signal representing the color of said second type, the first look-up table being representative of a multi-dimensional color space wherein each of the first color and second color of the first type relates to an axis in the color space; the second look-up table providing an output for each of a set of combinations of input signals representing the first color and second color of said first type, each output being a color signal representing the second color of said second type, the second look-up table being representative of a multi-dimensional color space wherein each of the first color and second color of the first type relates to an axis in the color space; wherein there exists a different arrangement of inputs along the axis in the first look-up table corresponding to the first color of the first type than along the axis in the second look-up table corresponding to the first color of the first type, the outputs of the first look-up table having a higher resolution along the axis corresponding to the first color of the first type than the outputs of the second look-up table corresponding to the first color of the first type; and means for applying color signals representing the first color and second color of said first type to the first look-up table and second look-up table.
Claim 2
Independent Claim 337 words
An apparatus for converting color signals representing at least a first color and second color of a first type to color signals representing at lease a first color and second color of a second type, comprising: a first look-up table and a second look-up table, each look-up table being a multi-dimensional look-up table defined in a memory accessible in real time and having as inputs predetermined color signals representing at least the first color and second color of said first type; the first look-up table providing an output for each of a set of combinations of inputs signals representing the first color and second color of said first type, each output being a color signal representing the color of said second type, the first look-up table being representative of a multi-dimensional color space wherein each of the first color and second color of the first type relates to an axis in the color space; the second look-up table providing an output for each of a set of combinations of input signals representing the first color and second color of said first type, each output being a color signal representing the second color of said second type, the second look-up table being representative of a multi-dimensional color space wherein each of the first color and second color of the first type relates to an axis in the color space; wherein there exists a different arrangement of inputs along the axis in the first look-up table corresponding to the first color of the first type than along the axis in the second look-up table corresponding to the first color of the first type, the outputs of the first look-up table having a higher resolution along the axis corresponding to the first color of the first type than the outputs of the second look-up table corresponding to the first color of the first type; and means for applying color signals representing the first color and second color of said first type to the first look-up table and second look-up table.
Claim 3
Dependent Claim 24 words
The apparatus of claim 1, wherein the color signals representing a first color and second color of a second type relate to CMY colors.
Claim 4
Dependent Claim 28 words
The apparatus of claim 1, further comprising means for applying color signals representing the first color and second color of said second type to a digital printing apparatus.
Claim 5
Dependent Claim 27 words
The apparatus of claim 1, further comprising means for performing undercolor removal on the color signals representing the first color and second color of said second type.
Claim 6
Independent Claim 313 words
An apparatus for converting color signals representing at least a first color and second color of a first type to color signals representing at least a first color and second color of a second type, comprising: a first look-up table and a second look-up table being a multi-dimensional look-up table defined in a memory accessible in real time and having as inputs predetermined color signals representing at least the first color second color of said first type; the first look-up table providing and output for each of a set of combinations of input signals representing the first color and second color of said first type, each output being a color signal representing the first color of said second type, the first look-up table being representative of a multi-dimensional color space wherein each of the first color and second color of the first type relates to an axis in the color space; the second look-up table providing an output for each of a set of combinations of input signals representing the first color and second color of said first type, each output being a color signal representing the second color of said second type, the second look-up table being representative of a multi-dimensional color space wherein each of the first color and second color of the first type relates to an axis in the color space; wherein there exists a different arrangement of inputs along the axis in the first look-up table corresponding to the first color of the first type than along the axis in the second look-up table corresponding to the first color of the first type; the outputs of the first look-up table being non-uniformly distributed along at least one axis in the color space; and means for applying color signals representing the first color and second color of said first type to the first look-up table and second look-up table.
Claim 7
Independent Claim 313 words
An apparatus for converting color signals representing at least a first color and second color of a first type to color signals representing at least a first color and second color of a second type, comprising: a first look-up table and a second look-up table being a multi-dimensional look-up table defined in a memory accessible in real time and having as inputs predetermined color signals representing at least the first color second color of said first type; the first look-up table providing and output for each of a set of combinations of input signals representing the first color and second color of said first type, each output being a color signal representing the first color of said second type, the first look-up table being representative of a multi-dimensional color space wherein each of the first color and second color of the first type relates to an axis in the color space; the second look-up table providing an output for each of a set of combinations of input signals representing the first color and second color of said first type, each output being a color signal representing the second color of said second type, the second look-up table being representative of a multi-dimensional color space wherein each of the first color and second color of the first type relates to an axis in the color space; wherein there exists a different arrangement of inputs along the axis in the first look-up table corresponding to the first color of the first type than along the axis in the second look-up table corresponding to the first color of the first type; the outputs of the first look-up table being non-uniformly distributed along at least one axis in the color space; and means for applying color signals representing the first color and second color of said first type to the first look-up table and second look-up table.
Claim 8
Independent Claim 336 words
An apparatus for converting color signals representing at least a first color and second color of a first type to color signals representing at least a first color and second color of a second type, comprising: a first look-up table and a second look-up table, each look-up table being a multi-dimensional look-up table defined in a memory accessible in real time and having as inputs predetermined color signals representing at least the first color and second color of said first type; the first look-up table providing an output for each of a set of combinations of input signals representing the first color and second color of said first type, each output being a color signal representing the first color of said second type, the first look-up table being representative of a multi-dimensional color space wherein each of the first color and second color of the first type relates to an axis in the color space; the second look-up table providing an output for each of a set of combinations of input signals representing the first color and second color of said first type, each output being a color signal representing the second color of said second type, the second look-up table being representative of a multi-dimensional color space wherein each of the first color and second color of the first type relates to an axis in the color space; wherein there exists a different arrangement of inputs along the axis in the first look-up table corresponding to the first color of the first type than along the axis in the second look-up table corresponding to the first color of the first type; wherein there exists a different arrangement of inputs in the first look-up table along the axis corresponding to the first color of the first type than along the axis corresponding to the second color of the first type; and means for applying color signals representing the first color and second color of said first type to the first look-up table and second look-up table.
Claim 9
Independent Claim 336 words
An apparatus for converting color signals representing at least a first color and second color of a first type to color signals representing at least a first color and second color of a second type, comprising: a first look-up table and a second look-up table, each look-up table being a multi-dimensional look-up table defined in a memory accessible in real time and having as inputs predetermined color signals representing at least the first color and second color of said first type; the first look-up table providing an output for each of a set of combinations of input signals representing the first color and second color of said first type, each output being a color signal representing the first color of said second type, the first look-up table being representative of a multi-dimensional color space wherein each of the first color and second color of the first type relates to an axis in the color space; the second look-up table providing an output for each of a set of combinations of input signals representing the first color and second color of said first type, each output being a color signal representing the second color of said second type, the second look-up table being representative of a multi-dimensional color space wherein each of the first color and second color of the first type relates to an axis in the color space; wherein there exists a different arrangement of inputs along the axis in the first look-up table corresponding to the first color of the first type than along the axis in the second look-up table corresponding to the first color of the first type; wherein there exists a different arrangement of inputs in the first look-up table along the axis corresponding to the first color of the first type than along the axis corresponding to the second color of the first type; and means for applying color signals representing the first color and second color of said first type to the first look-up table and second look-up table.
Claim 10
Independent Claim 371 words
An apparatus for converting color signals representing at least a first color and second of a first type color signals representing at least a first color and second color of a second type, comprising: a first look-up table and a second look-up table, each look-up table being a multi-dimensional look-up table defined in a memory accessible in real time and having as inputs predetermined color signals representing at least the first color and second color of said first type; the first look-up table providing and output for each of a set of combinations of the input signals representing the first color and second color of said first type, each output being a color signal representing the first color of said first type, the first look-up table being representative of a multi-dimensional color space wherein each of the first color and second color of the first type relates to an axis in the color space; the second look-up table providing an output for each of a set of combinations of input signals representing the first color and second color of said first type, each output being a color signal representing the second color of said second type, the second look-up table being representative of a multi-dimensional color space wherein each of the first color and second color of the first type relates to an axis in the color space; wherein there exists a different arrangement of inputs along the axis in the first look-up table corresponding to the first color of the first type than along the axis in the second look-up table corresponding to the first color of the first type; wherein there exists a different arrangement of inputs in the first look-up table alone the axis corresponding to the first color of the first type than along the axis corresponding to the second color of the first type, the outputs of the first look-up table having a higher resolution along the axis corresponding to the first color of the first type than along the axis corresponding to the second color of the first type; and means for applying color signals representing the first color and second color of said first type to the first look-up table and second look-up table.
Claim 11
Independent Claim 371 words
An apparatus for converting color signals representing at least a first color and second of a first type color signals representing at least a first color and second color of a second type, comprising: a first look-up table and a second look-up table, each look-up table being a multi-dimensional look-up table defined in a memory accessible in real time and having as inputs predetermined color signals representing at least the first color and second color of said first type; the first look-up table providing and output for each of a set of combinations of the input signals representing the first color and second color of said first type, each output being a color signal representing the first color of said first type, the first look-up table being representative of a multi-dimensional color space wherein each of the first color and second color of the first type relates to an axis in the color space; the second look-up table providing an output for each of a set of combinations of input signals representing the first color and second color of said first type, each output being a color signal representing the second color of said second type, the second look-up table being representative of a multi-dimensional color space wherein each of the first color and second color of the first type relates to an axis in the color space; wherein there exists a different arrangement of inputs along the axis in the first look-up table corresponding to the first color of the first type than along the axis in the second look-up table corresponding to the first color of the first type; wherein there exists a different arrangement of inputs in the first look-up table alone the axis corresponding to the first color of the first type than along the axis corresponding to the second color of the first type, the outputs of the first look-up table having a higher resolution along the axis corresponding to the first color of the first type than along the axis corresponding to the second color of the first type; and means for applying color signals representing the first color and second color of said first type to the first look-up table and second look-up table.

References Cited (Backward Citations)

US4887150A Cited
US4992862A Cited
US5087126A Cited
US5187570A Cited
US5077604A Cited
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US5293228A Cited
US5412491A Cited
US5528386A Cited
US5452017A Cited
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USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 2001-07-27 2002-01-26 2002-07-28 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 2005-07-27 2006-01-26 2006-07-28 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2009-07-27 2010-01-26 2010-07-28 $7700.00 Window Closed / Lapsed

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